import random
stu = [ ]
for c in 'ABCDEFGHIJ':
    yz = (c,random.randint(40,100))
    stu.append(yz)
print(stu)

score = sum([s[1] for s in stu])
print('平均分：',score / len(stu))
stu2 = [s for s in stu if s[1]<60]
print('不及格人数：',len(stu2))
